1. WHAT IS GROUNDWATER?
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Groundwater is the water found
underground in the cracks and
spaces in soil, sand and rock. It
is stored in and moves slowly
through geologic formations of
soil, sand and rocks called aquifers.
It is the water located beneath the
earth's surface in soil pore spaces
and in the fractures of rock
formations.
Groundwater is a highly useful and
often abundant resource.
Groundwater sustains
rivers, wetlands and lakes, as well
as subterranean ecosystems
within karst or alluvial aquifers.

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Typically, groundwater is thought of as
liquid water flowing through shallow
aquifers, but technically it can also
include soil, moisture, permafrost
(frozen soil), immobile water in very low
permeability bedrock, and
deep geothermal or oil formation water.
However, over-use, or overdraft, can
cause major problems to human users
and to the environment. The most
evident problem (as far as human
groundwater use is concerned) is a
lowering of the water table beyond the
reach of existing wells.
Wells must consequently be drilled
deeper to reach the groundwater; in
some places
(e.g., California, Texas and India) the
water table has dropped hundreds of
feet because of extensive well pumping
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Groundwater provides the United States
with half of its drinking water. It also
waters 40% of American agriculture.

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As ageing large-scale surface
irrigation schemes have become
increasingly inefficient, and
farmers have begun growing a
wider range of crops requiring
water on demand, the number
of groundwater wells in India
has exploded. In 1960, there
were fewer than 100,000 such
wells; by 2006 the figure had
risen to nearly 12 million. In
India, a possible solution to
over-use of groundwater is
emerging, known as
'groundwater recharge'. It
involves capturing rainwater
that would otherwise runoff, and using it to refill aquifers.
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In the Punjab region of India, for
example, groundwater levels have
dropped 10 meters since 1979, and
the rate of depletion is accelerating.

4. SUSTAINABILITY OF GROUNDWATER
Experts say the connection
between surface water and
groundwater has been
overlooked and that integration is
needed to protect water supply
and the ecosystem. “Unless
surface water is available to
recharge the
aquifers, groundwater levels will
decline,” said Carl Hauge, former
chief hydro geologist with the
Department of Water Resources
(DWR). “That is, when pumping
takes groundwater out of
aquifers, and there is no surface
water to recharge the
aquifer, groundwater levels
decline.”
In some places, groundwater use